What To Do When Muscles Don’t Grow
What do you do when muscles don’t grow?
How often do talented athletes suffer from the wrong type of training for their genes?
“The Sports Gene” is a book by David Epstein that shows the answers to these questions are not what you might expect. Epstein’s premise is that although genetics exert a powerful influence on athletic success, training and culture do make a difference.
There’s no clear path to achievement. Although exceptional eyesight for tennis players, an extra long Achilles tendon for high jumpers, or a mutation that gives sprinters “double” muscle can’t hurt.
Many practical points can be taken from the book and a few of the most relevant surround the issue of the best type of exercise for optimal health, athletic achievement, and body composition. Below are some of the most compelling points to guide you in your pursuit of muscle, leanness, beauty, gold medals, and a long life.
Point #1: Some people get strong and big by lifting weights. For others, it’s largely useless. Muscle growth is influenced by the proportion of fast- and slow-twitch muscle fibers, satellite cell makeup, and the expression of the myostatin gene.
One key to muscle growth is the stimulation of satellite cells. Muscle fibers have more than one nucleus, which act as “command centers” that control muscle function in the area. As a fiber grows, each nuclei “commands” an increasingly larger area. Once the fiber grows beyond a certain threshold, satellite cells are activated to form new nuclei so that the muscle can continue to grow.
Research shows that individual differences in gene and satellite cell activity dictate how people respond to strength training. A study of 66 people who did squats, leg press, and extensions found that muscle growth fell into three categories:
There were 17 extreme responders who experienced an average 50 percent increase in muscle fiber size, 32 moderate responders who grew 25 percent, and 17 non-responders who had no increase in muscle size at all.
An analysis of satellite cell makeup showed that the extreme responders who grew the most had the most satellite cells in their quadriceps to begin with. They were just waiting to be activated to build muscle. The extreme responders also experienced an increase in the number of satellite cells they had, which would allow for continued growth if the kept training.
In addition, extreme responders had certain genes turned on and others turned off, pointing to these genes as principle regulators of muscle growth. For example, IGF-IEa, MGF, and myogenin genes were turned on “the most” in extreme responders whereas they were off in non-responders.
The MGF gene, which is involved in expression of the hormone mechano growth factor, was turned up by 126 percent in extreme responders compared to 73 percent in moderate responders.
Myostatin is a protein that is genetically coded that signals a muscle to stop growing. So for maximal growth, you want low myostatin. In animals without myostatin, muscle growth explodes as it does in people with genetic mutations that decrease their myostatin levels.
Yet, muscle growth is possible even if you don’t have a genetic mutation that blunts myostatin. A study of 150 body builders found no myostatin mutants—they all had normal myostatin levels.
Studies suggest that strength training itself is one way to downregulate myostatin. Results aren’t profound, but just as heavy strength training will increase satellite cells, it should decrease myostatin as well.
Point #2: Just because an individual doesn’t respond to one type of training (most studies measure traditional hypertrophy-style training with 10 reps at 75 percent of the 1RM) doesn’t mean that they won’t get results from a different protocol.
You’ll be much more likely to get results and perform better if you let your muscle fiber makeup and body type dictate your training. For example, people vary greatly in their allotment of slow- and fast-twitch muscle fibers and will experience greater improvements if they train according to the fiber-type makeup.
It’s well known that slow-twitch fibers are smaller, require abundant oxygen, and have high endurance and low force. The fast-twitch fibers are larger, contract and tire quickly, and produce explosive force.
The fiber type mixes of athletes fit their sport. The calf muscles of sprinters are at least 75 percent fast-twitch, while distance runners have more slow-twitch fibers. For instance, Frank Shorter, who won the 1972 Olympic marathon, had 80 percent slow-twitch fibers in his leg muscles.
After Joachim Olsen, a Danish shot-putter, found out he had a much higher proportion of fast-twitch fibers in his shoulders, quads, and triceps than other top throwers, he modified his training to short cycles of extremely heavy lifting interspersed with de-loads. He experienced remarkable strength and muscle gains and went on to win the bronze medal at the 2004 Olympics.
Another Danish athlete who competed in sprint kayak continually fell short of making the Olympic team until he had his muscle fibers biopsied. He had 90 percent slow-twitch fibers. He switched to long-distance kayak and quickly became one of the top racers in the world.
Finally, an analysis of fiber types of Danish pro soccer players showed they have fewer fast-twitch fibers than the average untrained man on the street. The fastest players who had the higher proportion of fast-twitch profiles that you’d expect in soccer players were always getting lost to chronic injuries before reaching the top level.
The reason is that fast-twitch fibers are more susceptible to injury. Scientists believe that the training volume was too high and too aerobic for the faster players. The fast athletes were being sacrificed to the idea that the same hard training works for everyone.
#3: Don’t get scared off by the science of genetics. Practical tips for getting individual results include the following:
1) Don’t fall prey to dogma or rules that don’t work. From experience, you know that everyone has to modify the variables to get the best results.
2) Some people respond to volume, others to intensity, and others to high volume, low intensity. Do what works.
The harder the training, the less likely there are to be “non-responders.” The harder and smarter you work, the more likely you will get at least some response, even if it less than that experienced by your peers.
3) If a type of training isn’t working for you, try something else. Don’t stubbornly stick to a type of exercise just because someone else with a completely diverse genetic profile got results.
4) There are three documented ways to increase satellite cells if you aren’t an extreme responder (or even if you are). Try performing maximal load training, do eccentrics, and take creatine.
• Performing a training cycle for strength in which you do maximal lifts a few times will maximally activate the satellite cells you have. It may increase the number of satellite cells as well.
• Doing heavy eccentrics has also been found to increase satellite cells in type II muscle fibers by 75 percent and in mixed fibers by 25 percent.
• Taking creatine in conjunction with training has also been found to increase satellite cells and lead to greater muscle growth.
5) Strength training may down-regulate myostatin and allow for adaptations over the longer terms.
6) Genetic testing for various athletic and physiological traits is available. However, the degree to which the genes that are measured influence potential varies greatly. Be aware that genetic research for physiological performance is in the infant stages—myostatin was identified a mere 15 years ago—and genetic testing is unregulated.